The FA are facing a battle to keep highly-rated Fulham midfielder Fabio Carvalho as Portugal plot a move to secure the teenager's international future.
The 19-year-old is widely recognised as one of the brightest young talents in English football and is being groomed as future senior international.
But Sportsmail understands the Portugal FA have been monitoring Carvalho's progress closely since last season with a view to potentially persuading him to switch allegiances.
Portugal could look to fast-track the Fulham academy graduate into their Under-21 set-up in an effort to secure his long-term future.
Carvalho, who was born in Portugal and started his career in Benfica, has so far represented England up to Under 18 level.
The scenario poses a threat to the FA, who are understandably keen to tie down Carvalho given his undoubted ability.
But the lure of playing for his homeland could be an attractive proposition for Carvalho.
The teenager burst onto the scene last season, scoring on his full Premier League debut in Fulham's defeat to Southampton.
He made four top-flight appearances for the Cottagers in total last season and has continued his rapid progress this season, starting in five of Fulham's six Championship matches so far, scoring three times.
The FA have placed a major emphasis on trying to keep their most talented youngsters, who are of dual nationality, within their system.
Last season they lost Valencia forward Yunus Musah to the USA, despite the fact the former Arsenal forward played extensively for England juniors.
Wilfried Zaha, Alex Iwobi and Victor Moses are among the players England have lost in recent seasons, while the FA are bracing themselves for a battle to prevent Chelsea forward Calum Hudson-Odoi, who has played for the senior team, from switching to play for Ghana.